export default class AjaxUtil{
	constructor(){}
	getJson(url,callback){
		let xhr = new XMLHttpRequest();
    	xhr.responseType="json";
    	xhr.open("get",url,true);
    	xhr.addEventListener("readystatechange",()=>{
    		if (xhr.readyState == 4 && xhr.status == 200) {
    			callback(xhr);
    		}
    	},false);
    	xhr.send(null);
	}
}